Issue 10 - April 2003 : USING CHIEF COMPLAINT TO CATEGORIZE SYNDROMIC SURVEILLANCE SYNDROMES

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USING CHIEF COMPLAINT TO CATEGORIZE SYNDROMIC SURVEILLANCE SYNDROMES

Syndromic surveillance systems frequently depend on existing databases or forms used in the hospital Emergency Department. One of the more common questions we hear concerns which data fields (e.g., chief complaint, nurse’s notes or diagnosis) are most reliable for correctly identifying patient syndromes.

The Nation’s Capital Region recently published their findings comparing chief complaint with ED discharge diagnosis.(1)

This cooperative group of 25 hospitals has had an ongoing ED syndromic surveillance system in place since September 11, 2001. In their system, hospitals fax their ED logs to the appropriate health departments. The syndrome coding is done by a person at the health department based on the chief complaint or, if not available, ED discharge diagnosis. There is a rather complicated hierarchical matrix used to classify each patient into one of eight mutually exclusive syndromes: Death, sepsis, rash, respiratory illness, gastrointestinal illness, unspecified illness, neurologic illness, and other.

In this study, data from two hospitals were chosen because they provide both chief complaint and discharge diagnosis for each entry. 4,040 visits were reviewed by a trained individual. Initially, syndromes were assigned based on chief complaint alone. Next, the reviewer assigned syndromes based on ED discharge diagnosis. Finally, the two syndrome scores per patient were statistically tested to determine agreement between syndromes.

A total of 3,919 visits were included in the final analysis. Statistical analysis was performed using frequency counts for each syndrome. The kappa statistic was used to measure agreement between the two methods of assigning syndromes.

The overall agreement between chief complaint and discharge diagnosis was good for respiratory, gastrointestinal, death, and rash syndromes. The ‘unspecified infection’ category was in the midrange. These unspecified infection cases, such as “fever alone” or “other nonspecific complaints” were given a specific diagnosis after they were evaluated clinically.

There was poor agreement between chief complaint and discharge diagnosis with sepsis and neurologic syndromes. Of course, “sepsis” or “septic shock” are rarely used by patients to describe their complaint. The neurologic syndrome category is one specifically designed to pick up botulism or meningitis cases; however no cases of this type were diagnosed during the study period.

In conclusion, in this study population chief complaint provided enough information to effectively assign patients to syndrome for most of the categories used by this regional hospital group. However, the study also confirms the common-sense idea that more information is better than less. Including discharge diagnosis, patient vital signs, or nurses’ notes increases the likelihood that the patient will be placed in the correct syndrome category.

1) Bergier, Elizabeth., et. al. The National Capital Region’s Emergency Department Syndromic Surveillance System: Do Chief Complaint and Discharge Diagnosis Yield Different Results? Emerging Infectious Diseases 2003;9:393-396

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